Drilling-engine.



PATENTED SEPT. 8, 1903.

J. B. DAMAS'.

DRILLING ENGINE.

APPLICATION FILED MAY 26, 1903.

NO MODEL.

Patented September 8, 1903.

PATENT OFFICE.

JOHN B. DAMAS, OF SONORA, CALIFORNIA.

DRlLLlNG-ENGINE.

SPECIFICATION forming part of Letters Patent No.738,416, dated September8, 190,3. Applicant 'sied May 2s. 190e. serial No. 158,823. (No model.)

To all whom, it may concern:

4Be it known that I, JOHN B. DAMAS, a citizen of the United States,residing at Sonora,

county of Tuolumne, State of California, have invented an Improvement inDrilling and Like Reciprocating Engines; and Ihereby declareathefollowing to be a full, clear, and exact description of the same.

My invention relates to a reciprocating engine such as is employed fordrillingr and like purposes. Y

It consists of a cylinder having a doubleended piston reciprocatingtherein, the rod of said piston connecting at one end with the drill orother striking device, and in conjunction therewith of a valve havingports by which steam is admitted alternately at either end of thecylinder, and a second port and passage connecting with the cylinder atthe rear end and serving to act as a cushion to prevent the piston fromstriking the rear end of the cylinder. In conjunction with this is atilting or oscillating fulcrumed lever pivoted in a centrally-disposedchamber and having its lower separated ends so disposed withrelation tothe reduced central portion of the piston that the enlarged heads of thepiston serve to alternately tilt the lever and move the valve at theinstant when the piston arrives at either end of its stroke.

My invention also comprises details of construction, which will be morefully explained by reference to the accompanying drawings, in which-Figure l is a longitudinal vertical central section of my engine withvalve opened to admit steam into left end of cylinder. Fig. 2 is asection in same plane with valve opened to admit steam into right end ofcylinder.

Reciprocating engines which are operated without crank or iiy-wheel areespecially used for impelling rock-drills and like perforating orstriking mechanism, and by reason of there being no crank tolimit thelength of stroke it is necessary to provide some means for preventingthe piston striking the ends of the cylinder, and especially the rearend, since the forward impulse of the piston is communicated directlywith the vdrill or striker, and the impact of the striker against therock or other face takes place before the piston reaches the frontend ofthe cylinder.

It is therefore only necessary to provide a means for preventing thepiston striking the rear end of the cylinder, and this is the object ofmy invention.

As shown in the drawings, A is a cylinder having a double-ended andpacked piston 2 movable within it. This piston has a central portion 3of smallerdiameter than the ends, and this central portion is connectedwith the exhaust-chamber of the engine. 4 is a lever fulcrumed orpivoted within this central chamber, and the lower ends of the lever areseparated, as shown, and project into the path of the piston in such amanner that they are contiguous to the smaller central portion of thepiston, and when the piston reaches either end of itstravel it strikesone of these 1ever ends, and thus tilts the lever upon its pivot. Theupper end of the lever enters a socket or open-ing in the slide-valve 5,which valve is movable upon a suitable seat and within a valve-chamber,(shown at 5*.) The forward end of the cylinder is connected by port 6with the corresponding end of the valve-seat, and at the otherend aretwo ports7 and 8, which act, respectively, as steaminlet and exhaustports. The valve has a D-port or single chamber l1 made in its lowersurface corresponding with the steam-port 6, and it has a B-port or twochambers 9 and 10 at the opposite or' rear end which correspond with theports 7 and S. Depressed channels 12 and l2a are made transverselyacross the ends of the valveseat, and the valve is movable so as toproject over these channels alternately, and when in the position shownin Fig. l the chamber 1l at the left end of the valve is in suchposition that it connects the depression 12 and the port 6, so as toadmit steam into the left end of the cylinder, and thus force the pistontoward the rear end. When the valve is in this position, the chamber l0at the opposite end of the valve connects the port S with thecentralchamberin which the lever 4 oscillates, and through this chamber steamfrom the rear end of the cylinderis eX- hausted and escapes through theexhaustport 13, the two closely-packed fitting heads of the pistonpreventing any passage of steam at those points. While the valve is inthis IOC position, the chamber 9 of the valve covers Athe port 7 and ateach end rests upon and makes a tight joint with the valve-seat, so thatthere can be no escape of steam through the port 7. Consequently whenthe right end of the piston 2 has passed the exhaust-port S there willbe a body of 'steam inclosed between this port and the rear head of thecylinder, and as this steam cannot escape through the port 7 it forms acushion which prevents the piston striking the rear head of thecylinder, no matter at what speed it may be driven.

When the piston has reached the rear end of its stroke, the shoulderbetween the smaller portion 3 of the piston and the enlarged p0rltionv2at the left end will strike the left pro- Y jection of the Ytiltinglever 4 and will move it about its pivot, so as to moveV the valve V5into the position shown in Fig. 2. In this position the chamber 1l atthe left end of the valve connects the port 6 with the exhaustpassage 13through the central chamber, and the chamber 9 will stand in theposition to connect the depression 12 at the right end of the valve-seatwith the port 7, which now becomes a steam-inlet port, admitting steamat the extreme right end of the cylinder, and as the steam which waspreviously cushioned at that end of the cylinder still remains there isno loss by what is termed clearance. This position of the valve bringsthe chamber l0 into such position that it covers the port 8, the ends ofthe chamber tting upon the surface of the valve-seat, and thuspreventing any passage of steam through the port 8 while the piston ismoving toward the left end of the cylinder. By this construction it willbe seen that the port 8 serves only to exhaust steam from the right endof the cylinder, and while this is taking place the port 7 is closed, sothat the space between the ports 7 and 8 Within the cylinder serves toretain the cushioning-steam, but as soon as the -position of the valvehas been changed the port 7 becomes the steam-inlet port, and theseports thus alternate, one acting as the exhaust and the other as thesteam-port.

The back ofthe valve may have a projection or rib, asl shown at 14, andthis rib is adapted to travel against the interior top of thevalve-chamber, so as to insure the valve always traveling closelyagainst its seat and preventing its being forced up by the impact of thepiston against the cushioning-steam which might otherwise act throughthe port 7 into the temporarily-closed chamber 9.

The piston-rod 16 extends through the front end of the cylinder and hasconnected with it the drill or other implement-carrying head 17, throughwhich the power of the piston is applied to strike the blow. The drillmay be revolved by any suitable or Well-known ratchet mechanism, whichis not here shown, as forming no part of my present invention.

Having thus described myinvention, what I claim, and desire to secure byLetters Patent, is-

1. The combination in a reciprocating engine and the cylinder thereof,of a doubleheaded piston having a central section of less diameter thanthe ends, a valve slidable upon 7o a valve-seat, said valve having aD-port in the under side at the front end and a B-port in the under sideat the rear end, a centrallydisposed chamber between the cylinder andvalve-chamber, a lever pivoted within said chamber having the lower endsprojecting into the cylinder so as to be alternately tilted by themovement of the piston, a socket in the valve-face with which the upperend of the lever engages to reciprocate the valve, a single portconnecting the front end of the valve-chamber with the front end of thecylinder, and two separate ports entering the rearV end of the cylinder,onewo'fV said ports serving to admit steam and the other to exhaust thesteam upon the return stroke of the piston.

2. A reciprocating engine consisting of a cylinder, a double-endedpiston fitting therein, a valve-chamber .having a seat, a valve slidableon said seat having a single chamber at the front and two chambers atthe rear end, depressions at each end of the valveseat over which theends of the valve are alternately moved to connect the outer endchambers of the valves alternately, with steam-ports leading to the endsof the cylin-l der, a second port connecting with the rear end of thecylinder, said second port communicating through the second chamber ofthe valve with the exhaust when the valve is in position to receivesteam from the opposite' end, and the iirst port temporarily closing therear steam-port whereby a cushion is formed within the cylinder betweenthe two rear ports.

3. A reciprocating engine consisting of a cylinder, a piston havingheads at opposite ends tting the cylinder and an intermediate connectionof smaller diameter forming shoulders between itself and the heads, avalve movable within the valve-chamber having a single 'chamber formedin the front end, a port connecting the valve-seat with the front end ofthe cylinder, means for reciprocating the valve to alternately connectits forward chamber with the steam-port, and with a centrally-locatedexhaust-port, a steam-port extending from the valve-seat to the rear endof the cylinder, and a similarly-located ex- 12o haust-port opening intothe cylinder at a distance from the steam-port, chambers formed in therear end of the valve corresponding with the steam and exhaust ports,one of said chambers alternately opening and closing the 125exhaust-port, and the other chamber similarly opening and closing thesteam-port.

In witness whereof I hereunto set my hand.

IOO

JOHN B. DAMAS.

